Good day! 

Recently my keyfob (which I use everyday) had a flat battery. After replacing multiple times the red LED just keeps flashing and the car does not respond to button presses. The same happed with the spare key. I have two 3 button flip keys and now both have constantly blinking LED's. Any ideas why? 

 

Thanks in advance

Sounds like one of the buttons is stuck down so it's constantly transmitting and has lost synchronisation with the car.

 

Would suggest you try to check / unstick the buttons and then re such the fob

I did check every button but they all apper the be fine on both keyfobs